A known ignition interlock mechanism for a column-mounted shift control assembly is disclosed in Dzioba U.S. Pat. No. 4,821,605. This mechanism includes a latch plate pivotally mounted on an end of an arcuate shaped detent plate. The latch plate has a locking surface which is selectively positioned via the interaction of a key cylinder slot, a lock pin, a ramped plunger, and a cable to prevent removal of an operator lever positioning arm from the Park position prior to the key cylinder being unlocked. The latch plate also includes a positioning surface which, when engaged by the positioning arm upon its return to Park position, will pivot the latch plate to thereby move the plunger and permit the lock pin to leave the key cylinder slot and permit the key to be returned to its lock and remove position.